Thermionic rectifier



2 1934 H. w. PARKER 1,982,067

THERMIONIC RECTIFIER Filed 0012. 12, 1932 INVENTOR Henru W. Parker Patentecl Nov. 27, 1934 UNITED STATES THERDIIONIC RECTIFIER Henry W, Parker, Toronto, Ontario, Canada, assignor to Rogers Radio Tubes, Limited, To-.. ronto, Ontario, Canada, a corporation of Ontario, Canada Application October 12, 1932, Serial No. 637,393

3 Claims. (01. 250-275,);

My invention pertains to thermionic discharge devices and relates particularly to that type of such devices knows as rectifiers.

One of the objects contemplated by my invention comprises providing a thermionic rectifier of such form that the cathode life is increased over that now known.

Another object comprises producing a thermionic rectifier of such extreme simplicity that its fabrication in mass production is facilitated and thus rendered less costly.

A further object comprises producing a thermionic rectifier of such design that a more uniform product in mass production is attained.

A still further object comprises producing a thermionic rectifier having increased power output.

An additional object comprises producing a thermionic rectifier having maximum efiiciency of operation.

I accomplish all of the above noted desirable features by a unique form of rectifier in which the cathode, which may be either of the filamentary or indirectly heated type, is enclosed by a metallic shield provided With small apertures therein opposite which anodes are positioned. The cathode shield prevents positive ion bombardment of the active area of the cathode except directly opposite the apertures therein thus in operation positive ions may bombard and decrease the efiiciency of only a small percentage of the total area of the cathode. The life of the cathode and hence the useful life of the rectifier is thus increased. The shield also functions to I reradiate heat back to the cathode, thereby allowing a higher cathode temperature to be attained with the same cathode power input, thus increas ing the over-all efficiency of the rectifier. The total emission of the cathode is available for .either anode for full wave rectification, and thus the full cathode power is available for giving a much greater output than could be obtained by the use of thermionic rectifiers in general use employing two cathodes and two anodes for full wave rectification.

In the drawing accompanying and forming a part of this specification and in which like reference numerals designate corresponding parts throughout:

Fig. 1 is an enlarged elevation of my improved thermionic rectifier; and

Fig. 2 is a side elevation of the same.

Referring now to the figures, there is provided the usual vitreous blank or envelope 1 to which is cemented the usual base provided with contact prongs as shown. The envelope is provided with a press and stem 14 and there is provided within the envelope an attenuated atmosphere of a gas,

preferablymercury, although any type of ionizable gas may be used. The press 14 is provided With a plurality of standards 6, 18, 16, 15, 17, and 8 which extend, it will be noted, perpendicularly throughout their length above the press. This construction facilitates mass production and simplifies and cheapens the cost of construction of my rectifier as it eliminates the usual operation of bending or forming the electrode supporting standards.

The standards 15 and 16 serve as supports and contact terminals for the filamentary cathode 24 which is enclosed by the tubular or cylindrical metal shield 2. This shield is preferably made of polished cold rolled nickel and is provided with a cap 3 of the same material. A supporting hook 5 for the filament 24 is supported through an aperture in the cap 3 in a resilient manner by means of the helical spring 4.

There are provided in the shield 2, two small apertures 10 and 11 in the sides thereof and adiacent and opposite these apertures the anodes 7 and 9 respectively are maintained by means of the standards 6 and 8 respectively. Portions of each of these standards are enclosed by glass tubes 13 and 12, respectively, which are united with the press 14 to increase the insulation resistance between these standard and standards 18 and 1'7, respectively, which support the tubular cathode shield 2. The anode standards 6 and 8 are connected as indicated with the proper prongs on the tube base, as are the filament standards 15 and 16.

It will be noted that the tubular shield 2 is in electrical contact through the cap 3, spring 4, and filament hook 5 with the mid-point of the filament 24. The shield is therefore maintained at the filament potential. It will be also noted that the anode current is conducted through the apertureslo and 11, respectively, to the anodes '7 and 9, respectively, by short paths. The anodes are preferably made of small area and are constructed of carbonized nickel having a very high thermal emissivity and the area of the anodes is determined by the anode current desired in the tube design considered.

Thermionic rectifiers constructed as above described have been found to deliver twice the peak power of the ordinary type of full wave rectifier employing two cathodes and two anodes. As the positive ions may bombard only a portion of the total area of the cathode, the length of the cathode life and hence the tube life is obviously increased. Further, the total emission of the cathode is available for both anodes and therefore the full cathode power is available permitting much greater output than that achieved with the type of rectifier employing two cathodes and two anodes. The formof the tube is such that it facilitates mass production, eliminates the operation of forming and bending the electrode supporting standards and thus the construction is rendered less costly.

Having thus completely described my invention, what I claim as new and desire to secure by United States Letters Patent is as follows:

1. A thermionic rectifier comprising, anenvelope containing an attenuated gas,a capped metallic cylinder within said envelope, a filamentary cathode within said cylinder and resiliently supported from the cap of said cylinder,

the wall of said cylinder having a plurality of apertures'therein'and an anode maintained adjacent each of said apertures.

' v 2. A thermionic rectifier comprising, an envelope containing an attenuated gas, ,a press within said envelope, a plurality of standards held in said press and extending perpendicularly therefrom, a cathode connected to two of said standards, a metallic shield having a plurality of apertures in the sides thereof enclosing said cathode and supported by an additional pair of said standards, resilient means attached to said shield and supporting the upper extremity of said cathode and anodes each supported by an additional one of said standards adjacent said apertures respectively.

3. A thermionic rectifier comprising, an envelope containing an attenuated gas, a press within said envelope, a plurality of standards held in said press and extending perpendicularly throughout their length therefrom, acathode in the form of an electron emitting filament connected to two of said standards, a metallic shield having a plurality of apertures in the sides thereof enclosing said cathode and supported by an additional pair of said standards, resilient means attached to said shield and supporting the top portion of said cathodeand a plurality of anodes each supported by an additional one-of said standards adjacent said apertures respectively.

HENRY W. PARKER. 

